AS snappy as a felt-brim fedora, “The Curse of the Jade Scorpion” is Woody Allen’s most purely entertaining film in years, a romantic comedy set in a lavishly re-imagined Manhattan of 1940.

The Woodman has found a more than worthy sparring partner in Helen Hunt. They really click as a comic team – he as a bragging, misogynistic insurance investigator and she as a relentlessly humorless efficiency expert who’s on his case.

They regularly lob insults into each other’s offices and slam doors on each other.

Hostilities momentarily cease during a work-related celebration, when, as a gag, a nightclub magician (David Ogden Stiers) hypnotizes the battling duo. Lo and behind, under the influence, they confess their repressed lust for each other.

Unfortunately for C.W. (Allen), the hypnotist has hidden motives.

The turbaned crook uses a code word – “Istanbul” – to put C.W. back under, so the hypnotized C.W. can burglarize the same ritzy mansions in which he’s helped install security systems.

Even as a perplexed C.W. – who remembers nothing afterward – finds himself reluctantly turning to Betty Ann (Hunt) to clear himself of suspicion, C.W. keeps lapsing into spells.

He’s even more hilariously confused when the hypnotist activates Betty Ann’s larcenous – and latent romantic – feelings with the word “Constantinople.”

Complicating things even further in what may be Allen’s most plot-driven movie ever, the seemingly hard-hearted Betty Ann is being torn up by an affair with her married boss (Dan Aykroyd).

Meanwhile, C.W. himself is being pursued by a socialite femme fatale (Charlize Theron) who finds herself turned on by his schizophrenic behavior.

He, in turn, seems more interested in a secretary given to tight sweaters (Elizabeth Berkley of “Showgirls”), but can’t get to first base with her.

All of which is mostly an excuse to riff on movies like Bob Hope’s 1946 private-eye spoof “My Favorite Brunette,” as well as numerous film noirs of the era starring Woody’s beloved Humphrey Bogart and others.

Allen and Hunt may not make you forget Katharine Hepburn and Spencer Tracy – but they will make you forget their 29-year age difference.

“The Curse of the Jade Scorpion” is quite a pick-me-up for a summer movie season that, until this week, has been seriously devoid of laughs.